The limbic has been repeatedly implicated in abnormal human and animal behavior. The vomeronasal system represents a major exteroceptive input to the amygdala. Vomeronasal functioning appears to be related to those behaviors in which the amygdala plays a controlling role. The snake is presented as an ideal experimental subject for study of the amygdala because of its exceptionlly well developed vomeronasal system and the absence of a developed neocortex capable of controlling limbic system activity. Vomeronasal functioning will be studied by making use of snake trailing behavior for food, mate and aggregation. Lesions will be placed in animals trained to trail. The lesions will bilaterally remove components of the olfactoy and vomeronasal systems from the periphery to and including the amygdala. Additional tests will be developed for careful analysis of tongue flicking behavior in order to validate the concept that the function of tongue flicking is to bring chemical substances to the vomeronasal organ to be sensed.